In addition to good efficiency, such dual clutch transmissions have among other advantages the advantage that they can be connected automatically, in particular without an interruption of the tractive power, wherein a transitional stage can be preselected already in the non-activated transmission, which is then activated with a change of the power-shiftable clutches. In this case, odd gears in a sub-transmission (1,3, 5, etc.) and the even gears in another sub-transmission (2, 4, 6, etc.) are positioned by means of the corresponding gearwheel sets which can be drivingly connected for example via synchronous clutches to the respective input shaft or output shaft.
The axial length of the dual clutch transmission depends on the number of the gearwheel sets or gear stages that are arranged in the axial direction one after another in the dual clutch transmission. Each of the gear stages consists of at least two fixed and/or loose gearwheels. Between the gear stages are arranged the shift elements, wherein upon their activation, forward and reverse gears can be connected.
A generic type of a dual clutch transmission is provided with gearwheel sets that are switchable via shift elements, which build in particular exactly eight gear stages. The gear stages are arranged respectively in a first sub-transmission and in a second sub-transmission. Each of the sub-transmissions is provided with an input shaft as well as with a common output shaft. The input shafts, which are arranged coaxially to each other, can be alternately activated by means of a power-shiftable clutch, wherein to the first sub-transmission are assigned the even forward gears, and to the second sub-transmission are assigned the odd gears, which can be connected via the switching element during a gear shift. The dual clutch transmission is in addition also provided with an intermediate gear stage, which can be shifted either to the first sub-transmission or to the second sub-transmission.
From DE 10 2012 004 096 A1 is known a dual clutch transmission wherein reverse gearwheels are formed with two reverse gearwheels arranged on a common reverse gear shaft.